water system. Acetonitrile was purchased from PHARMCO-AAPER (Brookfield,
CT). Formic acid (88%), barium hydroxide, and calcium oxide were obtained
from Fisher Scientific (Fair Lawn, NJ). Metal magnesium turnings,
lithium hydroxide, potassium hydroxide, sodium formate, rubidium chloride,
cesium carbonate, and Formic acid-d2 (95
wt % in D2O, 98 atom % D) were obtained from Sigma-Aldrich
(Saint Louis, MO). Strontium carbonate was obtained from J. T. Baker
(Avantor, Center Valley, PA). H218O was purchased
from Cambridge Isotope Laboratories (Cambridge, MA). All chemicals
were used without further purification.